Disk array device and controlling method thereof

ABSTRACT

The present invention provides a storage unit system that can be connected to a plurality of different kinds of networks and a controlling method for a system LU of a storage device control unit required in such a storage unit system. In the storage unit system, to an LDEV of a storage device, it is possible to set a system LU for storing control information in the storage unit system itself and a user LU for writing write data sent from a host device, while a management terminal specifies a system LU or a user LU to set a path definition to the LDEV and a CHN inhibits an access to the system LU from the host device in accordance with distinction specified by the management terminal. Furthermore, a path of the system LU is automatically defined to a backup LU, so that the control information stored in the system LU is backed up to the backup LU.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of application Ser. No. 10/911,604,filed Aug. 5 ,2004. The present application claims priority fromJapanese patent application No. JP 2004-157348 filed on May 27, 2004,the content of which is hereby incorporated by reference into thisapplication.

BACKGROUND OF THE INVENTION

The present invention relates to a disk array device and a technique forcontrolling the same and, more particularly, to a technique effectivelyapplied to a controlling method of replication of a storage unit systemthat can be connected to a plurality of different kinds of networks.

The inventors of the present invention have examined a conventional diskarray device and a technique for controlling it and consequentlyunderstood as follows.

Recently, there has been a rapid increase in quantity of data to behandled in a computer system. To efficiently utilize and manage suchvast data, there has been developed a technique which connects aplurality of disk array devices (hereinafter “storage unit systems”) andan information processing. apparatus to each other through a dedicatednetwork (Storage Area Network, which is hereinafter abbreviated as“SAN”) so that high-speed and vast data access to the storage unitsystems can be realized. In order to realize high-speed data transfer byconnecting the storage unit systems and the information processingapparatus to each other, generally the network is built up using acommunication instrument that complies with a fiber channel protocol.

Meanwhile, there has been developed a network system referred to as anetwork attached storage (NAS), which connects a plurality of storageunit systems and an information processing apparatus to each otherthrough a network that uses a transmission control protocol/Internetprotocol (TCP/IP) so that the storage unit systems can be accessed at afile level. In the NAS, a device having a file system function isconnected to the storage unit system, so that it is possible for theinformation processing apparatus to gain access at a file level. SeeJapanese Patent Laid-open No. 2002-351703.

SUMMARY OF THE INVENTION

However, regarding the technique for controlling the conventional diskarray device, the above-mentioned inventors have found out thefollowings from the examined results.

For example, the conventional NAS has been realized by connecting theinformation processing apparatus having a TCP/IP communication functionand a file system function to the storage unit system not having them.Therefore, a space is required for installing this informationprocessing apparatus to be connected. Further, in many cases theinformation processing apparatus and the storage unit system areconnected to each other through the SAN because communication needs tobe performed at high speed. Accordingly, a communication controlinstrument and a communication control function need to be provided.

In view of the above, the present invention has been developed, and amain object of the present invention is to provide a storage unit systemthat can be connected to a plurality of different kinds of networks, andto provided a controlling method of replication of a system region of astorage device control unit required in such a storage unit system.

The above and other objects and novel characteristics will becomeapparent from the description of the specification and the accompanyingdrawings.

Outlines of representative ones of inventions disclosed in the presentapplication will be briefly described as follows.

The present invention is applied to a disk array device and acontrolling method thereof, the disk array device comprising: aplurality of storage devices for storing data: a storage device controlunit for controlling a data write or read operation to the plurality ofstorage devices; a connection portion connected to the storage devicecontrol unit; a plurality of channel control portions for receiving awrite or read request from an external host device of the disk arraydevice itself, converting file-level data sent from the host device intoblock-level data, and transferring it to the plurality of storagedevices so that these data pieces may be classified into a plurality ofcluster groups; a shared memory storing control information exchangedbetween the plurality of channel control portions and the storage devicecontrol unit; a cache memory temporarily saving data exchanged betweenthe plurality of channel control portions and the storage device controlunit; and a management terminal for setting a logical configuration ofthe plurality of storage devices. Further, the present invention has thefollowing characteristics.

That is, in the present invention, in a plurality of LDEVs which arelogical storage regions of the plurality of storage devices, a system LUwhich is a storage region for storing control information in the diskarray device itself and a user LU which is a storage region for writingwrite data sent from the host device are settable; the managementterminal specifies the system LU or the user LU in order to set a pathdefinition with respect to the plurality of LDEVs; and the plurality ofchannel control portions each inhibit an access to the system LU fromthe host device in accordance with distinction of the system LU or theuser LU specified by the management terminal.

Further, in the present invention, in the plurality of LDEVs of theplurality of storage devices, a backup LU which is a storage region forbacking up the control information stored in the system LU is settable;and a path of the system LU is automatically defined with respect to thebackup LU, and the control information stored in the system LU is backedup with respect to the backup LU.

More specifically, the function to automatically define the path of thesystem LU is realized by the management terminal and the plurality ofchannel control portions; the management terminal assigns the system LUof which a path definition is desired, to the settable LDEV of theplurality of LDEVs; and the plurality of channel control portions eachdefine automatically a path of the system LU with respect to the backupLU of the settable LDEV assigned by the management terminal.

Or, the function to automatically define the path of the system LU isrealized by the plurality of channel control portions; and the pluralityof channel control portions each assign the system LU for which a pathdefinition is desired, to the settable LDEV of the plurality of LDEVs,and define automatically a path of the system LU with respect to thebackup LU of the settable LDEV assigned.

Alternatively, the function to automatically define the path of thesystem LU is realized by the management terminal; and the managementterminal assigns the system LU for which a path definition is desired,to the settable LDEV of the plurality of LDEVs, and definesautomatically a path of the system LU with respect to the backup LU ofthe settable LDEV assigned.

For example, the control information stored in the system LU is OSinformation, dump information, command device information, faultinformation, or cluster-shared information; and the OS information, dumpinformation, command device information, fault information, orcluster-shared information is backed up to the backup LU.

Effects obtained by representative ones of inventions disclosed in thepresent invention will be briefly described as follows.

According to the present invention, it is possible to provide a storageunit system that can be connected to a plurality of different kinds ofnetworks, and further to provide a controlling method for replication ofa system region of a storage device control unit that is required insuch a storage unit system. In particular, it is possible to, inaccordance with settings by maintenance people or users, separate asystem LU and a user LU from each other explicitly and specify a backupLU only for the system LU and also automatically set definition of apath and a decrease in number of paths provided so that access can begained from each package according to a predetermined policy.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram for showing an overall configuration of asystem that includes a storage unit system according to one embodimentof the present invention.

FIG. 2 is a diagram showing a configuration of a management terminal inthe storage unit system according to the one embodiment of the presentinvention.

FIG. 3 is a diagram showing a physical disk management table in thestorage unit system according to the one embodiment of the presentinvention.

FIG. 4 is a diagram showing an LU management table in the storage unitsystem according to the one embodiment of the present invention.

FIG. 5 is a diagram showing a hardware configuration of a channelcontrol portion in the storage unit system according to the oneembodiment of the present invention.

FIG. 6 is an explanatory diagram for describing contents of data to bestored in a memory in the storage unit system according to the oneembodiment of the present invention.

FIG. 7 is a diagram showing meta data in the storage unit systemaccording to the one embodiment of the present invention.

FIG. 8A is a diagram showing lock data in the storage unit systemaccording to the one embodiment of the present invention.

FIG. 8B is a diagram showing lock data in the storage unit systemaccording to the one embodiment of the present invention.

FIG. 9 is a diagram showing a hardware configuration of a disk controlportion in the storage unit system according to the one embodiment ofthe present invention.

FIG. 10 is a diagram showing a software configuration in the storageunit system according to the one embodiment of the present invention.

FIG. 11 is a diagram showing an outline of an LUN definition in thestorage unit system according to the one embodiment of the presentinvention.

FIG. 12 is a diagram showing roles of a system LU in the storage unitsystem according to the one embodiment of the present invention.

FIG. 13 is a diagram showing a relationship between an OS storing LU andits backup LU in the storage unit system according to the one embodimentof the present invention.

FIG. 14 is a diagram showing a relationship between a dump storing LUand its backup LU in the storage unit system according to the oneembodiment of the present invention.

FIG. 15 is a diagram showing a relationship between a command device LUand its backup LU in the storage unit system according to the oneembodiment of the present invention.

FIG. 16 is a diagram showing a relationship between a fault informationstoring LU and its backup LU in the storage unit system according to theone embodiment of the present invention.

FIG. 17 is a diagram showing a relationship between a clusterinformation storing LU and its backup LU in the storage unit systemaccording to the one embodiment of the present invention.

FIG. 18 is a diagram showing roles of a user LU in the storage unitsystem according to the one embodiment of the present invention.

FIG. 19 is a diagram showing an LUN definition for host group #00 in thestorage unit system according to the one embodiment of the presentinvention.

FIG. 20 is a diagram showing an LUN definition for an OS-storing LU inthe storage unit system according to the one embodiment of the presentinvention.

FIG. 21 is a diagram showing an LUN definition for a dump pick-up LU inthe storage unit system according to the one embodiment of the presentinvention.

FIG. 22 is a diagram showing an LUN definition for a backup LU of theOS-storing LU in the storage unit system according to the one embodimentof the present invention.

FIG. 23 is a diagram showing an LUN definition for a backup LU of acluster-shared information storing LU in the storage unit systemaccording to the one embodiment of the present invention.

FIG. 24 is a diagram showing an LUN definition for other system LUs inthe storage unit system according to the one embodiment of the presentinvention.

FIG. 25 is a flowchart showing a processing for a path definition of abackup LU in the storage unit system according to the one embodiment ofthe present invention.

FIG. 26 is a flowchart for showing processings for path definitions ofvarious LUs plus backup LUs by an SVP-and-NAS blade-led method in thestorage unit system according to the one embodiment of the presentinvention.

FIG. 27 is a diagram showing a basic screen of a management terminal inthe storage unit system according to the one embodiment of the presentinvention.

FIG. 28 is a diagram showing an LUN-addition screen of the managementterminal in the storage unit system according to the one embodiment ofthe present invention.

FIG. 29 is a flowchart showing processings for path definitions ofvarious kinds of LUs plus backup LUs by an NAS blade (NASOS)-led methodin the storage unit system according to the one embodiment of thepresent invention.

FIG. 30 is a flowchart showing processings for path definitions ofvarious kinds of LUs plus backup LUs by an SVP-led method in the storageunit system according to the one embodiment of the present invention.

FIG. 31 is a diagram showing an LUN definition for host group #01 in thestorage unit system according to the one embodiment of the presentinvention.

FIG. 32 is a diagram showing an LUN definition for a user LU in thestorage unit system according to the one embodiment of the presentinvention.

FIG. 33 is a diagram showing a module configuration of the managementterminal in the storage unit system according to the one embodiment ofthe present invention.

FIG. 34 is a diagram showing an outline of a function of each module inthe storage unit system according to the one embodiment of the presentinvention.

FIG. 35 is a diagram showing permission/inhibition of setting in an LUNdefinition in the storage unit system according to the one embodiment ofthe present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, an embodiment of the present invention will be detailedbased on the drawings. Note that the members having the same functionare denoted by the same reference symbol in principle throughout all thedrawings for explaining the embodiments and the repetitive descriptionthereof will not be omitted.

<Overall Configuration Example of System Including Storage Unit System>

The following will describe one example of an overall configuration of asystem including a storage unit system according to an embodiment withreference to FIG. 1. FIG. 1 is a block diagram for showing an overallconfiguration of a system that includes a storage unit system.

A storage unit system 600 according to the present embodiment comprisesa storage device control unit 100 and a storage device 300. The storagedevice control unit 100 controls the storage device 300 in accordancewith a command received from an information processing apparatus 200.For example, it receives a data input/output request from theinformation processing apparatus and performs processing for inputtingand outputting data to and from the storage device 300. The data isstored in a logical volume (which is a logical unit and hereinafterabbreviated as “LU”), i.e. a storage region logically set in a physicalstorage region provided by a disk drive that the storage device 300 has.Further, the storage device 100 exchanges various commands for managingthe storage unit system 600 with the information processing apparatus200.

The information processing apparatus 200 is a computer provided with acentral processing unit (CPU) and a memory. The CPU of the informationprocessing apparatus 200 executes various programs, thereby realizingvarious functions. The information processing apparatus 200 may be, forexample, a personal computer or a workstation as well as a mainframecomputer.

In FIG. 1, the information processing apparatuses (1) 200 through (3)200 are connected to the storage device control unit 100 via a localarea network (LAN) 400. The LAN400 may be the Internet or a dedicatednetwork. Communication is established between the information processingapparatuses (1) 200 through (3) 200 and the storage device control unit10 via the LAN 400 in accordance with, for example, the TCP/IP. Theinformation processing apparatuses (1) 200 through (3) 200 transmit tothe storage unit system 600 a data access request by specification of afile name (which is a data input/output request for each file andhereinafter written also as a “file access request”).

To the LAN 400, a backup device 910 is connected. The backup device 910is specifically a disk device such as an MO, CD-R, or DVD-RAM or a tapedevice such as a DAT tape, cassette tape, open-reel tape, or cartridgetape. The backup device 910 communicates with the storage device controlunit 100 via the LAN 400, thereby storing backup data of data stored inthe storage device 300. Further, the backup device 910 may also beconnected to the information processing apparatus (1) 200. In this case,backup data of the data stored in the storage device 300 is intended tobe acquired through the information processing apparatus (1) 200.

The storage device control unit 100 is provided with channel controlportions (1) 110 through (4) 110. The device control unit 100 receivesfile access requests individually from the information processingapparatuses (1) 200 through (3) 200, from the channel control portions(1) 110 through (4) 110 via the LAN 400. That is, the channel controlportions (1) 110 through (4) 110 are each assigned a network address onthe LAN 400 (e.g., IP address) beforehand and behave individually as anNAS, and therefore can give a service as the NAS to the informationprocessing apparatuses (1) 200 through (3) 200 as if the individual NASis an independent one. Hereinafter, each of the channel control portions(1) 110 through (4) 110 is written also as a “CHN”. In such a manner,the one storage unit system 600 is provided in configuration with thechannel control portions (1) 110 through (4) 110, each of which gives aservice individually as an NAS, whereby NAS servers conventionallyoperated by individually independent computers are integrated into onestorage unit system 600. It is therefore possible to conduct blanketcontrol over the storage unit system 600 and thereby to promoteefficient maintenance such as various settings and control, hazardmanagement, and version management.

Note that the channel control portions (1) 110 through (4) 110 of thestorage device control unit 100 according to the present embodiment are,as described later, realized by hardware formed in an integrated unitcircuit board and an operating system (hereinafter written as “OS” also)executed by this hardware or by software such as an application programthat operates on this OS or executable object codes executed by thishardware. In such a manner, in the storage unit system 600 according tothe present embodiment, functions conventionally mounted as part of thehardware are realized by the software. Therefore, in the storage unitsystem 600 of the present embodiment, a system operation is possiblewith sufficient flexibility, whereby it is possible to providesophisticated services based on multifarious user needs that changerapidly.

The information processing apparatuses (3) 200 and (4) 200 are connectedto the storage device control unit 100 via a storage area network (SAN)500. The SAN 500 is a network for exchanging data with the informationprocessing apparatuses (3) 200 and (4) 200 by using, as one unit, ablock that is a data management unit in a storage region provided by thestorage device 300. Communication between the storage device controlunit 100 and the information processing apparatuses (3) 200 and (4) 200via the SAN 500 is typically established in accordance with a fiberchannel protocol. From the information processing apparatuses (3) 200and (4) 200, data access requests (hereinafter written as “block accessrequests”) are transmitted to the storage unit system 600 in units of ablock in accordance with the fiber channel protocol.

The storage device control unit 100 communicates with the informationprocessing apparatuses (3) 200 and (4) 200 through the channel controlportions (5) 110 and (6) 110. Hereinafter, each of the channel controlportions (5) 110 and (6) 110 is written as a “CHF” also.

To the SAN 500, backup device 900 that accommodates an SAN is connected.The backup device 900 that accommodates the SAN communicates with thestorage device control unit 100 via the SAN 500, thereby storing backupdata of the data stored in the storage device 300.

The information processing apparatus (5) 200 is connected to the storagedevice control unit 100 neither through the LAN 400 nor through the SAN500. The information processing apparatus (5) 200 may be, for example, amainframe computer. Communication between the information processingapparatus (5) 200 and the storage device control unit 100 is establishedin accordance with a communication protocol such as FICON (FibreConnection) (Registered Trademark), ESCON (Enterprise System Connection)(Registered Trademark), ACONARC (Advanced Connection Architecture)(Registered Trademark), or FIBARC (Fibre Connection Architecture)(Registered Trademark). From the information processing apparatus (5)200, a block access request is transmitted to the storage unit system600 in these communication protocols.

The storage device control unit 100 communicates with the informationprocessing apparatus (5) 200 through the channel control portions (7)110 and (8) 110. Hereinafter, each of the channel control portions (7)110 and (8) 110 is written as a “CHA” also.

To the SAN 500, there is connected another storage unit system 610 whichis installed to a location (secondary site) far away from aninstallation site (primary site) of the storage unit system 600. Thestorage unit system 610 is utilized as an apparatus of a datareplication destination in a replication or remote-copy function asdescribed later. Note that the storage unit system 610 is in some casesconnected to the storage unit system 600 via a communication line suchas an ATM other than the SAN 500. In this case, for example, the channelcontrol portion 110 provided with an interface (channel extender) forutilizing the above-mentioned communication line is employed as thechannel control portion 110.

<Storage Device>

The storage device 300 is equipped with a number of disk drives(physical disks) and provides a storage region to the informationprocessing apparatus 200. Data is stored beforehand in an LU, which is astorage region logically set in a physical storage region provided bythe disk drive. The disk drive may be any one of various drives such asa hard disk unit, a flexible disk unit, and a semiconductor storageunit. Note that, in the storage device 300, for example, a plurality ofdisk drives can be combined to configure a disk array. In this case, astorage region to be provided to the information processing apparatus200 may be configured by using a plurality of disk drives managed by aredundant array of inexpensive disks (RAID).

The storage device control unit 100 and the storage device 300 may beconnected in direct connection form as shown in FIG. 1 or through anetwork. Furthermore, the storage device 300 can be formed integrallywith the storage device control unit 100.

The LU to be set to the storage device 300 may be a user LU accessiblefrom the information processing apparatus 200, and a system LU used forcontrolling the channel control portion 110, etc. The system LU storesalso the OS to be executed by the CHN 110. Further, each of the LUs iscorrelated with each channel control portion 110. With this, eachchannel control portion 110 is assigned an accessible LU. Further, inthis correlation, a plurality ones of the channel control portions 110may share one LU. Note that hereinafter the user LU and the system LUare written also as a “user disk” and a “system disk” respectively.

<Storage Device Control Unit>

The storage device control unit 100 comprises the channel controlportion 110, the shared memory 120, a cache memory 130, a disk controlportion 140, a management terminal 160, and a connection portion 150.

The channel control portion 110 is provided with a communicationinterface for communicating with the information processing apparatus200, thus having a function to exchange a data input/output command withthe information processing apparatus 200. For example, the CHN 110receives a file access request sent from the information processingapparatuses (1) 200 through (3) 200. Due to this, the storage unitsystem 600 can provide a serve as an NAS to the information processingapparatuses (1) 200 through (3) 200. Further, the CHF 110 receives ablock access request sent from the information processing apparatuses(3) 200 and (4) 200 in accordance with the fiber channel protocol. Forthis reason, the storage unit system 600 can provide, to the informationprocessing apparatuses (3) 200 and (4) 200, a data storage servicecapable of high-speed access. Further, the CHA 110 receives a blockaccess request sent from the information processing apparatus (5) 200 inaccordance with a protocol such as FICON, ESCON, ACONARC, or FIBERC.Thereby, the storage unit system 600 can provide the data storageservice also to the mainframe computer such as the informationprocessing apparatus (5) 200.

The channel control portions 110 as well as the management terminal 160are mutually connected through a communication network such as aninternal LAN 151. This enables to transmit, from the management terminal160, a micro-program etc. to be executed by the channel control portion110 so that the program may be installed. A configuration of the channelcontrol portion 110 will be described later.

The connection portion 150 is connected to the channel control portion110, the shared memory 120, the cache memory 130, and the disk controlportion 140. Data and commands are exchanged among the channel controlportion 110, the shared memory 120, the cache memory 130, and the diskcontrol portion 140 via the connection portion 150. The connectionportion 150 is comprised of, for example, a bus or a switch such as anultra-high speed crossbar switch for transferring data by high-speedswitching. Since the channel control portions 110 are connected to eachother through the switch, performance of communication between thechannel control portions 11 is greatly improved as compared to that of aconventional configuration in which the channel control portions areconnected to each other through the LAN by the NAS server operating oneach of the computers. Due to this, a file sharing function and/orhigh-speed fail-over can be achieved.

The shared memory 120 and the cache memory 130 is a storage memoryshared by the channel control portion 110 and the disk control portion140. The shared memory 120 is mainly utilized to store controlinformation and commands, whereas the cache memory 130 is mainlyutilized to store data.

For example, in the case where a data input/output command received byone of the channel control portions 110 from the information processingapparatus 200 is a write command, the one channel control portion 110writes the write command into the shared memory 120 and also writes,into the cache memory 130, write data received from the informationprocessing apparatus 200. Meanwhile, when the disk control portion 140monitoring the shared memory 120 detects that the write command iswritten into the shared memory 120, it reads the write data from thecache memory 130 in accordance with this command and writes it into thestorage device 300.

Further, for example, in the case where a data input/output commandreceived by one of the channel control portions 110 from the informationprocessing apparatus 200 is a read command, the one channel controlportion 110 writes the read command into the shared memory 120 andreads, from the cache memory 130, data demanded by the read command fromthe information processing apparatus 200. If the data demanded by theread command has not been written in the cache memory 130, the channelcontrol portion 110 or the disk control portion 140 reads, from thestorage device 300, data demanded by the read command and writes it intothe cache memory 130.

Note that although in this embodiment the shared memory 120 and thecache memory 130 have been described as being provided independently ofthe channel control portion 110 and the disk control portion 140, thepresent invention is not limited to this and the shared memory 120 andthe cache memory 130 are preferably provided separately in the channelcontrol portion 110 and the disk control portion 140. In this case, theconnection portion 150 mutually connects the channel control portion 110and the disk control portion 140, each of which has either one of theshared memory 120 and the cache memory 130.

The disk control portion 140 controls the storage device 300. Forexample, as described above, data is written into the storage device 300in accordance with a data write command received by the channel controlportion 110 from the information processing apparatus 200. Further, adata access request for an LU by specification of a logical addresstransmitted from the channel control portion 110 is converted into adata access request for a physical disk by specification of a physicaladdress. In the case where the physical disk in the storage device 300is managed by an RAID, data access in accordance with an RAIDconfiguration is executed. Further, the disk control portion 140controls replication management and backup of data stored in the storagedevice 300. Furthermore, to prevent vanishing of data at the time ofdisaster occurrence (disaster recovery), the disk control portion 140conducts control so as to store a replica of data of the storage unitsystem 600 installed at the primary site also in the other storage unitsystem 610 installed at the secondary site (replication function orremote copy function).

The respective disk control portions 140 as well as the managementterminal 160 are connected to each other through a communication networksuch as the internal LAN 151 and can communicate with each other. Due tothis, a micro-program etc. to be executed by the disk control portion140 is transmitted from the management terminal 160 so that it may beinstalled. A configuration of the disk control portion 140 will bedescribed later.

<Management Terminal>

The management terminal 160 is a computer for maintenance and managementof the storage unit system 600. By operating the management terminal160, it is possible to, for example, set a configuration of a physicaldisk in the storage device 300 and set the LU, and install amicro-program to be executed by the channel control portion 110 or thedisk control portion 140. As for this setting of a physical diskconfiguration in the storage device 300, for example, the number of thephysical disks can be increased or decreased and an RAID configurationcan be changed (e.g., from RAID1 to RAID5).

Furthermore, the management terminal 160 can confirm an operation stateof the storage unit system 600 and identify a location of a trouble, andinstall the OS to be executed by the channel control portion 110.Further, the management terminal 160 is connected to an externalmaintenance center through a LAN or a telephone circuit and, therefore,can be utilized to monitor a fault of the storage unit system 600 andcope with it rapidly when it has occurred. Occurrence of a fault isnotified by, for example, an OS, application program, or driversoftware, etc. This notification is, for example, a HTTP protocol,Simple Network Management Protocol (SNMP), or e-mail, etc. These settingand control operations are performed by an operator who uses, as a userinterface, a Web page provided by a Web server that operates in themanagement terminal 160. The operator etc. can operate the managementterminal 160 to set a target and contents that are subject to faultmonitoring or to a destination to be notified of the fault.

The management terminal 160 may be in built-in form of the storagedevice control unit 100 or in externally mounted form. Further, themanagement terminal 160 may be used as a dedicated computer formaintenance and management of the storage device control unit 100 andthe storage device 300 or as a general-purpose computer provided withthe maintenance and management functions.

<Configuration Example of Management Terminal>

The following will describe one configuration example of the managementterminal in the storage unit system according to the present embodimentwith reference to FIGS. 2 to 4. FIG. 2 is a diagram showing aconfiguration of the management terminal; FIG. 3 is a diagram showing aphysical disk management table; and FIG. 4 is a diagram showing an LUmanagement table.

As shown in FIG. 2, the management terminal 160 comprises a CPU 161, amemory 162, a port 163, a storage medium reading unit 164, an input unit165, an output unit 166, and a storage unit 168.

The CPU 161 controls the entirety of the management terminal 160 andexecute a program 162 c stored in the memory 162, thereby realizing afunction as a Web server. In the memory 162, a physical disk managementtable 162 a, an LU management table 162 b, and the program 162 c arestored.

The physical disk management table 162 a is a table for managing aphysical disk (disk drive) equipped to the storage device 300. Thisphysical disk management table 162 a is shown in, for example, FIG. 3.In FIG. 3, the physical disks having disk numbers #001 through #006 of anumber of physical disks equipped to the storage device 300 areindicated. For each of the physical disks, its capacity, RAIDconfiguration, and busy condition are indicated.

The LU management table 162 b is a table for managing an LU logicallyset on the above-mentioned physical disk. This LU management table 162 bis shown in, for example, FIG. 4. In FIG. 4, the LUs having LU numbers#1 through #3 of a number of LUs set in the storage device 300 areindicated. For each of the LUs, its physical disk number, capacity, andRAID configuration are indicated.

The storage medium reading unit 164 is a unit for reading programs anddata recorded in a recording medium 167. The read programs and data arestored in the memory 162 or the storage unit 168. Therefore, it ispossible, for example, to read the program 162 c recorded in therecording medium 167 through the recording medium 167 by using therecording medium reading unit 164 and to store it in the memory 162 orthe storage unit 168. As the recording medium 167, for example, aflexible disk, a CD-ROM, or a semiconductor memory can be used. Therecording medium reading unit 164 can also be contained in themanagement terminal 160.

The storage unit 168 may be, for example, a hard disk unit, a flexibledisk unit, or a semiconductor memory. The input unit 165 is used by theoperator etc. to enter data to the management terminal 160. As the inputunit 165, for example, a keyboard or a mouse is used. The output unit166 is a unit for outputting information to the outside. As the outputunit 166, for example, a display or a printer is used. The port 163 isconnected to the internal LAN 151, so that the management terminal 160can communicate with the channel control portion 110, and the diskcontrol portion 140, etc. Further, the port 163 may be connected to theLAN 400 or the telephone circuit.

<Configuration Example of Channel Control Portion>

The following will describe one example of a configuration of thechannel control portion in the storage unit system according to thepresent embodiment with reference to FIGS. 5 to 8. FIG. 5 is a diagramshowing a hardware configuration of the channel control portion; FIG. 6is an explanatory diagram for describing contents of data to be storedin the memory; FIG. 7 is a diagram showing meta data; and FIGS. 8A and8B are diagrams showing lock data.

As described above, the storage unit system 600 according to the presentembodiment receives a file access request through the CHN 110 from theinformation processing apparatuses (1) 200 through (3) 200 and providesa service as an NAS to the information processing apparatuses (1) 200through (3) 200.

As shown in FIG. 5, hardware of the CHN 110 is constituted as one unit.Hereinafter this unit is written as an “NAS board”. The NAS board iscomprised of one or a plurality of circuit boards. More specifically,the NAS board comprises a network interface portion 111, an input/outputcontrol portion 114, a board-connecting connector 116, a communicationconnector 117, and a file server portion 800 that are all formed in thesame unit. Furthermore, the input/output control portion 114 has anon-volatile RAM (NVRAM) 115 and an input/output (I/O) processor 119.

The network interface portion 111 is provided with a communicationinterface for communicating with the information processing apparatus200. In the case of the CHN 110, a file access request transmitted fromthe information processing apparatus 200 in accordance with, forexample, the TCP/IP protocol is received. The communication connector117 is a connector for communicating with the information processingapparatus 200. In the case of the CHN 110, it is a connector connectableto the LAN 400 and accommodates, for example, Ethernet (RegisteredTrademark).

The file server portion 800 has a CPU 112, a memory 113, a BasicInput/Output System (BIOS) 801, and an NVRAM 804. The CPU 112 hascontrol for making the CHN 110 function as the NAS board.

The CPU 112 performs such processing as: analysis of a file accessrequest by file specification; mutual transposition by use of aconversion table (not shown) between file-unit data to controlinformation in the memory 113 in the process of activating the CPU 112and an LU in the storage device 300; generation of a data write/readrequest to an LU in the storage device 300; transmission of a datawrite/read request to the I/O processor 119; and the like. The BIOS 801is software to be loaded first in the memory 113 and executed forexample upon power application of the CHN 110 and saved in anon-volatile medium such as a flash memory and installed in the CHN 110.

The CPU 112 can execute software read from the BIOS 801 into the memory113, thereby initializing and diagnosing portions related with the CPU112 in the CHN 110. Furthermore, the CPU 112 can issue an instructionsuch as a command from the BIOS 801 to the I/O processor 119, therebyreading a predetermined program, for example, a boot portion of the OSfrom the storage device 300 into the memory 113. The read OS bootportion acts to further read a main portion of the OS stored in thestorage device 300 into the memory 113, to thus activate the OS in theCPU 112, in which the OS can in turn execute processing as, for example,a file server. Further, the file server portion 800 is mounted with theNVRAM 804 for storing a network boot loader that is compliant with aprescription such as Preboot Execution Environment (PXE) and can performa network boot operation described later.

Various programs and data are stored in the memory 113. For example,meta data 730 or a lock table 720 shown in FIG. 6 and various programssuch as an NAS manager 706 shown in FIG. 10 are stored. The meta data730 is information generated in accordance with a file managed by a filesystem. The meta data 730 contains information required to identify afile storage location, such as an LU address of stored file data or adata size. The meta data 730 may in some cases contain information suchas a file capacity, owner, or update time. Further, the meta data 730may be created not only in accordance with a file but also with adirectory. An example of the meta data 730 is shown in FIG. 7. The metadata 730 is stored also in each of the LUs in the storage device 300.

The lock table 720 is arranged to conduct exclusive control on fileaccess placed from the information processing apparatuses (1) 200through (3) 200. By exclusive control, a file can be shared by theinformation processing apparatuses (1) 200 through (3) 200. The locktable 720 is such as shown in, for example, FIG. 8. As shown in FIG. 8,the lock table 720 has a file lock table 721 as shown in FIG. 8A and anLU lock table 722 as shown in FIG. 8B. The file lock table 721 indicateswhether each file is locked. If a file is made open by one of theinformation processing apparatuses 200, this file is locked. This lockedfile is inhibited from being accessed from any other informationprocessing apparatuses 200. The LU lock table 722 indicates whether eachof the LUs is locked. If an LU is being accessed by one of theinformation processing apparatuses 200, this LU is locked. The locked LUis inhibited from being accessed by any other information processingapparatuses 200.

The input/output control portion 114 exchanges data and commands amongthe disk control portion 140, the cache memory 130, the shared memory120, and the management terminal 160. The input/output control portion114 is equipped with the I/O processor 119 and the NVRAM 115. The I/Oprocessor 119 is constituted of, for example, a one-chip microcomputer.The I/O processor 119 controls transfer of data and data write/readrequests to the LUs in the storage device 300 and relays communicationbetween the CPU 112 and the disk control portion 140. The NVRAM 115 is anon-volatile memory for storing a program that controls the I/Oprocessor 119. Contents of the program stored in the NVRAM 115 can besubject to write and rewrite operations due to an instruction from themanagement terminal 160 and the NAS manager 706 described later.

<Configuration Example of Disk Control Portion>

The following will describe one example of a configuration of the diskcontrol portion in the storage unit system according to the presentembodiment with reference to FIG. 9. FIG. 9 is a diagram showing ahardware configuration of the disk control portion.

As described already, the disk control portion 140 is connected to thestorage device 300 and also connected through the connection portion 150to the CHN 110, so that the disk control unit 140 writes data to andreads it from the storage device 300 either independently or under thecontrol of the CHN 110.

The disk control portion 140 comprises an interface portion 141, a CPU142, a memory 143, an NVRAM 144, and a board-connecting connector 145,which are all formed into an integral unit.

The interface portion 141 is equipped with: a communication interfacefor communicating with the channel control portion 110 etc. via theconnection portion 150; a communication interface for communicating withthe storage device 300; and a communication interface for communicatingwith the management terminal 160 via the internal LAN 151.

The CPU 142 controls the entirety of the disk control portion 140 andcommunicates with the channel control portion 110 as well as the storagedevice 300 and the management terminal 160. By executing the variousprograms stored in the memory 143 or the NVRAM 144, functions of thedisk control portion 140 of the present embodiment are realized. Thefunctions realized by the disk control portion 140 include control ofthe storage device 300 and the RAID, replication management and controlof the data stored in the storage device 300, and control on remotecopy.

The NVRAM 144 is a no-volatile memory for storing a program thatcontrols the CPU 142. Contents of the program stored in the NVRAM 144can be subject to write and rewrite operations in accordance with aninstruction from the management terminal 160 or the NAS manager 706.

Further, the disk control portion 140 is equipped with theboard-connecting connector 145. When the board-connecting connector 145is connected to a connector on the side of the storage device controlunit 100, the disk control unit 140 is electrically connected to thestorage device control unit 100.

<Software Configuration Example>

The following will describe an example of a software configuration inthe storage unit system according to the present embodiment withreference to FIG. 10. FIG. 10 is a diagram showing a softwareconfiguration in the storage unit system.

As described already, on the CHN 110, the CPU 112 and the I/O processor119 exist. The CPUs 112 and the I/O processors 119 may be provided oneor more, respectively. the CPU 112 operates as an NAS server when an OS701 and various applications such as the NAS manager 706 are executed inthe CPU 112. In the I/O processor 119, a micro-program serving as acontroller operates. At the disk control portion 140, an RAID controlportion 740 operates in the CPU 142.

In the management terminal 160, the CPU 161 operates as a network bootserver 703. The network boot server 703 transfers a mini-kernel 704, andan OS image 705, etc. from the recording medium 167 or the storage unit168 through the internal LAN 151 to the CPU 112 on the CHAN 110. Thenetwork boot server 703 has, for example, a Dynamic Host ConfigurationProtocol (DHCP) server to assign an IP address or an MAC address to theCPU 112, the CPU 161, and the I/O processor 119, thereby transferringdata between the management terminal 160 and each of the CPU 112, theCPU 161, and the I/O processor 119. To boot a network, for example, theCPU 112 makes a request as a client to the network boot server 703 forDHCP, and file transfer, etc. The CPU 112 operates the mini-kernel 704in the CPU 112 through a procedure for network booting. Finally, the CPU112 causes the OS image 705 to be installed in the storage device 300via the I/O processor 119.

Note that FIG. 10 is a diagram explicitly showing also a softwareconfiguration of the information processing apparatus 200. Theinformation processing apparatus 200 may have a network file system(NFS) 711 or a common Internet file system (CIFS) 713. The NFS 711 is afile-sharing protocol which is mainly used in an UNIX (RegisteredTrademark) base operating system 714 and the CIFS 713 is a file-sharingprotocol which is mainly used in a Windows (Registered Trademark) baseOS 715.

<Defining Method of System LU and User LU>

As described above, the storage unit system according to the presentembodiment comprises: the plurality of storage devices 300 for storingdata; the plurality of disk control portions (storage device controlportions) 140 for controlling the data write/read operations to theplurality of storage devices 300; the connection portion 150 forconnecting to the disk control portion 140; the plurality of CHNs(channel control portions) 110 for receiving a write/read request fromthe external information processing apparatus (host device) of thisstorage unit system, converting file-level data sent from theinformation processing apparatus 200 into block-level data, andtransferring it to the plurality of storage devices 300 so that thesedata pieces may be classified into a plurality of cluster groups; theshared memory 120 in which control information transferred between theplurality of CHNs 110 and the plurality of disk control portions 140 isstored; the cache memory 130 in which data transferred between theplurality of CHNs 110 and the plurality of disk control portions 140 issaved temporarily; and the management terminal 160 for setting a logicalconfiguration of the plurality of storage devices 300.

Although details are omitted, in such a configuration, a system LU whichis a storage region for storing control information in this storage unitsystem and a user LU which is a storage region for writing therein writedata sent from the information processing apparatus 200 can be set in aplurality of LDEVs which is a logical storage region of the plurality ofstorage devices 300, the management terminal 160 specifies the system LUor the user LU in order to set path definition for the plurality ofLDEVs, and the plurality of CHNs 110 inhibits the information processingapparatus 200 from accessing the system LU according to distinctionbetween the system LU and the user LU specified by the managementterminal 160.

Furthermore, in the plurality of LDEVs of the plurality of storagedevices 300, a backup LU which is a storage region for backing upcontrol information stored in the system LU can be set, so that a pathof the system LU is automatically defined for the backup LU to back upcontrol information stored in the system LU for the backup LU.Specifically, a function to automatically define the path of the systemLU can be realized by a combination of the management terminal 160 andthe CHN 110, the CHN 110, or the management terminal 160.

In particular, in the storage unit system of the present embodiment, thedefinition and the function of the system LU and the user LU as viewedfrom LUN management software (LUN Management) which is connected throughthe internal LAN and exists in the storage unit system or the managementterminal installed outside a frame can be realized as follows.

Only host groups #00 and #01 of host groups are defined as default bythe management terminal 160 so that they may not be changed or deleted.Further, a new host group may not be added either. Host group 300 fixesNAS-Sys as a name and means a system LU. Host group #01 fixes User as aname and means a user LU.

<Outline of LUN Definition>

The following will describe one example of an outline of an LUNdefinition in the storage unit system according to the presentembodiment with reference to FIG. 11. FIG. 11 is a diagram showing anoutline of an LUN definition in the storage unit system.

For example, in the storage unit system having the pluralities ofNAS-package CHNs 110, and SAN-package CHN 110, the storage device 300,etc. as shown in FIG. 11, an LU which is set to the storage device 300may be a system LU to be used for control of the CHN 110 or a user LUaccessible from the information processing apparatus 200; in eithercase, the LU is each correlated with the CHN 110. With this, the CHN 110is each assigned an accessible LU.

To host group #00, an access path to a system LU is defined. An LUN ofthis host group #00 provides a setting of the system LU, so that theuser or a maintenance man sets LUN #00, 01, 05, 06, 08, 0A, 4B, 4C, and4D and, further, as the system LU of the NAS packages, LUN #0B, 0C, 0D,0E, 0F, 10, 12, 1B, 1C, 1D, 1E, 1F, 20, 22, 2B, 2C, 2D, 2E, 2F, 30, 32,3B, 3C, 3D, 3E, 3F, 40, and 42 are automatically set. It is permitted toset a command device to LUN #05 of host group #00. In host group #00,setting of a command device to any other LUN # is invalidated. Detailsof this system LU are described later.

Further, to host group #01, an access path to a user LU is set. An LUNof this host group #01 provides a setting of the user LU. The LUN ofhost group #01 permits setting of a command device to any LUN. Detailsof this user LU are described later.

In the storage unit system of the present embodiment, in order toguarantee a high availability, a plurality of CHNs can be combined asone suite to complement each other in operation. A unit of operationsgiven by this plurality of CHNs is referred to as a cluster. The CHNsbelonging to a cluster share a path to LUs in which user data is stored,so that an appropriate one of the LUs can be accessed even if the userissues a request to any one of the CHNs from a client. However,definition of a path is information which is recognized by a controllermicro-program of the I/O processor in the storage unit system, so thatto permit the OS to access this LU, it is necessary to mount a filesystem. If the path is not defined yet, existence of this LU is nottransmitted from the controller micro-program to the OS, so that itcannot be mounted; if the path is defined, on the other hand, when theOS makes an inquiry to the controller micro-program, the controllermicro-program can transmit the existence of this LU to the OS.

That is, to permit the OS to access this LU, first the existence of thisLU needs to be posted from the controller micro-program when thecontroller micro-program has defined an access path to this LU and theOS has inquired the controller micro-program for any available devices;furthermore, the OS creates a file system for at least one or, at themaximum, all of those devices posted as being available and then mountsthis file system.

It is to be noted that this creation of a file system refers topermitting the OS to access data by specifying a file name or adirectory name to such a device, defining a structure of the file or thedirectory, defining a rule for accessing that structure, and storingthese information pieces in both a system region and a data region.Further, the mounting of a file system refers to registering this filesystem. A file system can be mounted or canceled by an instruction fromthe OS. This canceling of mounting is referred to as un-mounting. In thecase of the present system, the system region exits in the system LU andthe data region exists in the user LU. The OS operates the file ordirectory structure in accordance with this rule, to access data. Thisaccess method is referred to as file system access.

<Roles of Various LUs>

The following will describe one example of roles of each of the LUs.FIG. 12 is a diagram showing roles of the system LU; FIG. 13 is adiagram showing a relationship between an OS-storing LU and its backupLU; FIG. 14 is a diagram showing a relationship between a dump storingLU and its backup LU; FIG. 15 is a diagram showing a relationshipbetween a command device LU and its backup LU; FIG. 16 is a diagramshowing a relationship between a fault information storing LU and itsbackup LU; FIG. 17 is a diagram showing a relationship between a clusterinformation storing LU and its backup LU; and FIG. 18 is a diagramshowing roles of the user LU.

As shown in FIG. 12, the system LU of host group #00 may be: theOS-storing LU of LUN #00; the command-device LU of LUN #05; the faultinformation-storing LU of LUN #06; the cluster-shared informationstoring LU of LUN #08; the backup LU of LUN #0A of the cluster-sharedinformation storing LU; the backup LU of LUN #4B of the dump storing LU;the backup LU of LUN #4C of the command device LU; or the backup LU ofLUN #4D of the fault information storing LU.

(1) LUN #00 (OS Storing LU) and LUN #09 (Backup LU of OS Storing LU) . .. FIG. 13

In LUN #00 (OS storing LU) of the storage device 300, the OS is firstinstalled from the management terminal 160 via the internal LN over thenetwork. When triggered by power-ON of the CHN 110 (expansion,replacement, software-wise instruction from the management terminal 160,etc.), the BIOS 801 of the CPU 112 due to an OS operation boots the OSstored in LUN #00, which the OS in turn operates in the CPU 112, thusproviding functions as a file server. The OS operating in the CPU 112due to the OS operation backs up stored OS files and their settings inLUN #09 (backup LU of the OS storing LU).

(2) LUN #01 (Dump Storing LU) and LUN #4B (Backup LU of the Dump StoringLU) . . . FIG. 14

If the OS is disabled to continue operating owing to a software faultetc., the BIOS 801 writes data of the entirety or a portion of a memoryused by the OS to LUN #01 (dump storing LU) and then stops the OS.Thereafter, to resume services, the OS needs to be restarted. Whenoperating (during ordinary time or after being restarted), the OS backsup contents of LUN #01 into LUN #4B (backup LU of the dump storing LU).Further, if the OS is halted due to a fault etc., the contents of LUN#01 are backed up from another CHN into LUN #4B. A trigger for backup isto be picked up periodically or when instructed to do so by themanagement terminal 160.

(3) LUN #05 (Command Device LU) and LUN #4C (Backup LU of Command DeviceLU) . . . FIG. 15

LUN #05 (command device LU) refers to a dummy LU that is required toissue an instruction for a particular application operating on the OSfrom a client using this particular application. It is required becausean LU must be specified by all means in order to issue a command.Therefore, no data exists in a command device itself. When the OS issuesto the I/O processor 119 a command for a command device, the I/Oprocessor 119 executes a DKC-specific function such as remote copy incooperation with the OS. The OS is triggered by an instruction from themanagement terminal 160 to thereby assign any other LUN that can be usedas the command device. In this case, LUN #4C (backup LU of commanddevice LU) does not copy data, to give an image for preparing apreliminary command device, which also may be referred to as a kind ofbackup.

(4) LUN #06 (Fault Information Storing LU) and LUN #4D (Backup LU ofFault Information Storing LU) . . . FIG. 16

LUN #06 (fault information storing LU) refers to an LU which is preparedin order that mainly another CHN (because an original CHN is assumed tobe halted at the time of fault occurrence) may perform processing suchas compression on dump data written into the above-mentioned dumpstoring LU and store its results. A backup of the data after beingprocessed is created from mainly another CHN for LUN #4D (backup LU offault information storing LU) of another LU.

(5) LUN #08 (Cluster Information Storing LU) and LUN #0A (Backup LU ofCluster Information Storing LU) . . . FIG. 17

In an NAS, one CHN package plays a role of one file server. However,when a plurality of CHNs belongs to the same cluster and if one of theseCHNs cannot continue its processing owing to a fault, another CHN takesover the processing by logical definition to perform an fail-overoperation of continuing a file server service etc. for the client. Inthis case, as information required to take over the processing, LUN #08(cluster information storing LU) is defined. In this case, if one toeight CHN packages can be, for example, installed to the storage unitsystem, a plurality of clusters can be present as mixed in the storageunit system. However, if the cluster information storing LU cannot beused owing to a fault, none of the clusters can perform fail-overoperation (when the CHN cannot be used owing to a fault in thiscondition also, none of the clusters can take over the processing). Toavoid this, a backup of a cluster information storing LU is picked upbeforehand from an arbitrary CHN during ordinary time for LUN #0A of aspecific LU.

As shown in FIG. 18, a user LU of host group #01 refers to an LU whichis required for CHN 110 operating as a file server to be opened to aclient (information processing apparatus 200) on a user LAN and providefile services. The user can exert his authority to create, view, delete,and replicate a file in this LU. The LU can take on any value of up to amaximum (FF in this case, i.e., 256 in total).

<Definition of System LU>

The following will describe one example of definition of a system LUwith reference to FIGS. 19 to 24. FIG. 19 is a diagram showing an LUNdefinition for host group #00; FIG. 20 is a diagram showing an LUNdefinition for an OS-storing LU; FIG. 21 is a diagram showing an LUNdefinition for a dump pick-up LU; FIG. 22 is a diagram showing an LUNdefinition for a backup LU of the OS-storing LU; FIG. 23 is a diagramshowing an LUN definition for a backup LU of a cluster-sharedinformation storing LU; and FIG. 24 is a diagram showing an LUNdefinition for other system LU.

As shown in FIG. 19, a system LU is defined in host group #00. Note thatin a system LU, only an LUN definition shown in FIG. 19 is permitted asone example. Further, although a minimum capacity of an LDEV in which anLU can be defined is such as shown in FIG. 19, there are differences incapacity of an LDEV that can be set depending on an individual LU. Notethat one to eight CHNs can be, for example, installed in an example ofFIG. 19.

Specifically, as one example, LUN #00 has contents of an OS storing LUand a minimum capacity of LDEV of 200 MB. Similarly, LUN #01 is a dumppick-up LU and a capacity of 100 MB, LUN #05 is a command device LU andhas a capacity of 50 MB, LUN #06 is a fault information storing LU andhas a capacity of 70 MB, LUN #08 is a cluster-shared information storingLU and has a capacity of 60 MB, LUN #09 is a backup LU of an OS storingLU and has a capacity of 200 MB, LUN #0A is a backup LU of acluster-shared information storing LU and has a capacity of 60 MB, LUN#4B is a backup LU of a command device LU and has a capacity of 100 MB,LUN #4C is a backup LU of a command device LU and has a capacity of 50MB, and LUN #4D is a backup LU of a fault information storing LU and hasa capacity of 70 MB.

Further, LUNs #0B to 12 are used to store the OS and automatically addedand deleted depending on whether LUN #00 of CHNs 1 to 8 exists and havea capacity of 200 MB, LUN #1B to 22 are used to pick up a dump andautomatically added and deleted depending on whether LUN #01 of CHNs 1to 8 exists and have a capacity of 100 MB, LUN #2B to 32 are used toback up the OS and automatically added and deleted depending on whetherLUN #09 of CHNs 1 to 8 exists and have a capacity of 200 MB, and LUN #3Bto 42 are used to back up cluster-shared information and automaticallyadded and deleted depending on whether LUN #0A of CHNs 1 to 8 exists andhave a capacity of 60 MB.

In FIG. 19, “automatically added or deleted depending on whether LUN #00of CHN 1 exists” described in “Contents” means that when the user or themaintenance man issues, from the management terminal, an instruction fordefining a path in a relevant package (CHN 1 in this example), themanagement terminal and the package decide whether a path of LUN#00 isalready defined in CHN 1 and, is such is the case, automatically setthis LU (LUN #0B in the above-mentioned example) and, otherwise, do notset this LU. Further, in a case where a relevant LU (LUN #0B) is alreadydefined when it is decided that path definition is not performed, thisLU is automatically deleted from the path definition. Path definitionitself is held in a form of a correlation table between an LUN and anLDEV present in the storage unit system in a non-volatile storage region(memory or hard disk) in the management terminal, a memory in eachpackage, and a shared memory in the storage unit system.

Setting of LUNs #00, 01, 05, 06, 08, 09, 0A, 4B, 4C, and 4D ispermitted. Further, setting of a device (LDEV) for which an access pathis already defined is not permitted.

LUNs #0B to 12, LUNs #1B to 22, LUNs #2B to 32, and LUNs #3B to 42 areto be set automatically.

To delete LUN #00, related LUNs (#0B to 12) of the other CHNs are alsodeleted (LUNs #0B to 12 are deleted when a related OS storing LU isdeleted).

To delete LUN #01, related LUNs (#1B to 22) of the other CHNs are alsodeleted (LUNs #1B to 22 are deleted when a related dump pick-up LU isdeleted).

To delete LUN #09, related LUNs (#2B to 32) of the other CHNs are alsodeleted (LUNs #2B to 32 are deleted when a backup LU of an OS storing LUis deleted).

To delete LUN #0A, related LUNs (#3B to 42) of the other CHNs are alsodeleted (LUNs #3B to 42 are deleted when a backup LU of a cluster-sharedinformation storing LU is deleted).

LUNs #05, 06, 08, 4B, 4C, and 4D are assigned the same LDEVs as theother CHNs 05, 06, 08, 4B, 4C, and 4D. Specifically, once LUNs #05, 06,08, 4B, 4C, and 4D are assigned to an LDEV for a network I/F on the sameCHN, it is indicated that only this LDEV can be selected when performingassignment on other CHNs.

To LUN #05, a command device is set. If a command device is yet to beset, it is set.

To delete a system LU, a user LU must not exist; if it exists, deletionof the system LU by the management terminal fails, resulting in anerror. This is done so in order to prevent a system indispensable toaccess user data such as the OS from being uninstalled in a conditionwhere the user data exists. However, deletion of a backup of the systemLU may be permitted even in a condition where a user LU exists.

(1) OS Storing LU

As shown in FIG. 20, LUNs #0B to 12 of group #00 in the storage unitdevice 300 are automatically set when LUN #00 of each CHN 110 isdetermined. Further, to delete LUN #00 (LUN #00 of CHN 1 in the figure),LUNs (which indicate LUN #0B of CHNs 2 to 8 in the figure) set in theother CHNs 110 are also deleted. However, to delete LUN #00, existenceof a user LU is not to be permitted (If a user LU exists, LUN #00 cannotbe deleted). It is to be noted that in each CHN, groups #00 of twonetwork I/Fs perform completely the same LUN definition. Further, LUN#0B of CHN 1 is yet to be defined.

(2) Dump Pick-up LU

As shown in FIG. 21, LUNs #1B to 22 of group #00 in the storage device300 are set automatically when LUN #01 of each CHN is determined.Further, to delete LUN #10 (LUN #01 in CHN 1 in the figure), LUNs (whichindicate LUN #1B of CHNs 2 to 8 in the figure) set in the other CHNs 110are also deleted. However, to delete LUN #10, existence of a user LU isnot to be permitted (If a user LU exists, LUN #01 cannot be deleted). Itis to be noted that in each CHN, groups #00 of two network I/Fs performcompletely the same LUN definition. Further, LUN #1B of CHN 1 is yet tobe defined.

(3) Backup LU of OS Storing LU

As shown in FIG. 22, LUNs #2B to 32 of group #00 in the storage device300 are set automatically when LUN #09 of each CHN is determined.Further, to delete LUN #09 (LUN #09 in CHN 1 in the figure), LUNs (whichindicate LUN #2B of CHNs 2 to 8 in the figure) set in the other CHNs 110are also deleted. However, to delete LUN #09, it is possible to set sothat existence of a user LU may not be permitted (If a user LU exists,LUN #09 cannot be deleted) or may be permitted. It is to be noted thatin each CHN, groups #00 of two network I/Fs perform completely the sameLUN definition. Further, LUN #2B of CHN 1 is yet to be defined.

(4) Backup LU of Cluster-shared Information Storing LU

As shown in FIG. 23, LUNs #3B to 42 of group #00 in the storage device300 are set automatically when LUN #0A of each CHN is determined.Further, to delete LUN #0A (LUN #0A in CHN 1 in the figure), LUNs (whichindicate LUN #3B of CHNs 2 to 8 in the figure) set in the other CHNs 110are also deleted. However, to delete LUN #0A, it is possible to set sothat existence of a user LU may not be permitted (If a user LU exists,LUN #0A cannot be deleted) or may be permitted. It is to be noted thatin each CHN, groups #00 of two network I/Fs perform completely the sameLUN definition. Further, LUN #3B of CHN 1 is yet to be defined.

(5) Other System LUs (Command Device LU, Fault Information Storing LU,Cluster-shared Information Storing LU, Backup LU of Dump Storing LU,Backup LU of Command Device LU, Backup LU of Fault Information StoringLU)

If LUNs #05, 06, 08, 4B, 4C, and 4D (only LUNs 05, 06, and 08 of themare shown in the figure) in the storage device 300 are determined in oneCHN 110 as shown in FIG. 24, LUNs #05, 06, 08, 4B, 4C, and 4D of theother CHNs 110 are to be assigned to the same LDEV. It is to be notedthat to delete LUNs #05, 06, 08, 4B, 4C, and 4D, existence of a user LUis not to be permitted (if a user LU exists, LUNs #05, 06, 08, 4B, 4C,and 4D cannot be deleted). Further, only an LUN of a selected package isto be deleted. It should be noted that it is necessary to set a commanddevice to an LDEV assigned to LUN #05. If a command device is not set,it is set, and if an LDEV to which a command device is set is selected,it is left as it is. It is to be noted that it is permitted to set acommand device to and release it from an LDEV which is assigned to LUN#05.

<Processing for Path Definition of Backup LU>

The following will describe one example of processing for defining apath of a backup LU with reference FIG. 25. FIG. 25 is a flowchart forshowing a processing for a path definition of a backup LU.

It is here assumed that the user enters data on a screen of themanagement terminal (written as SVP also) 160. An LDEV refers to a diskdrive image logically held in an RAID in the storage device 300. An LU,on the other hand, refers to a logical disk drive image that can berecognized by an NAS engine and a client and an LUIN indicates an LUNnumber. When the SVP specifies an LDEV to be assigned to an LUN, alogical drive in an RAID can be recognized by the NAS engine and theclient.

After start, first the user selects a port for which path definition isdesired (S1). This causes all LDEVs not yet assigned to an LUN to bedisplayed at the SVP (S2). Then, the user selects a fixed LU (S3). Thisfixed LU has a shade of meaning as a backup LU and determined in asspecifications. With this, a necessary capacity of this LUN isdetermined (S4). For example, in the case of a backup of an OS storingLU, a capacity of 200 MB is necessary. All LDEVs that satisfy thisnecessary capacity are displayed at the SVP (S5). In this case, thecapacity is checked.

Furthermore, the user selects one of these displayed LDEVs and relatesit to the LUN (S6). This causes this LUN to be decided whether it needsto be referenced by other ports also (S7). If is it decided that the LUNneeds to be referenced (Yes), a fixed LU is set to this LDEV for all ofthe other ports and the processing ends (S8). This fixed LUN has ameaning to be “a path to a backup LU of another port” and is determinedin specifications beforehand. Further, decision comes up withnon-necessity of referencing (No), the processing ends.

<Processing for Path Definitions of Various LUs Plus Backup LUs bySVP-and-NAS Blade-led Method>

The following will describe one example of processing for pathdefinitions of various LUs plus backup LUs by an SVP-and-NAS blade-ledmethod with reference to FIGS. 26 to 28. FIG. 26 is a flowchart forshowing processings for path definitions of various LUs plus backup LUsby the SVP-and-NAS blade-led method; FIG. 27 is a diagram showing abasic screen of the management terminal; and FIG. 28 is a diagramshowing an LUN-addition screen of the management terminal. Note thathereinafter the management terminal is written as the SVP and the NASpackage, as the NAS blade.

Items to be displayed to the SVP 160 in this processing include, forexample, (1) slot position of CHN, (2) port of CHN, (3) flag indicatingeither system LU or user LU (e.g., LU type), (4) list of LUs that can beset, (5) meanings of LUNs that can be set (e.g., OS storing LU, OSbackup LU, etc.), (6) list of available LDEVs (including LDEV size),etc. such as shown on the basic screen of FIG. 27 or the LUN-additionscreen.

Further, items to be input from the SVP 160 include (1) selection ofslot position of CHN, (2) selection of CHN port, (3) selection of eithersystem LU or user LU, (4) selection of one of LUNs that can be set, (5)selection of one of LDEVs that are thus displayed and can be set, etc.

Specifically, in an example of the basic screen of FIG. 27 are provideda region to give a hierarchical display of apparatuses in the storageunit system (DKC), a region to display host groups, a region to displayLUNs, etc. In the host group display region, host group #00 (NAS-Sys)and host group #01 (User) are displayed. That is, a type of a systemLU/user LU is displayed. In the LUN display region are provided regionssuch as LUN, CU: LDEV, Emulation, CVS, Size, Cmd.Dev, Cmd.Sec, andContent, which can be set and released by the maintenance man.

In an example of the LUN-addition screen of FIG. 28 are provided aregion to display host groups, a region to display LUNs, a region todisplay LDEVs, etc. In the LUN display region, each LUN# is displayed,so that only one LU is selected at a time and only LUNs to be set aredisplayed. If an LUN is already set to another CHN, only its LDEV isdisplayed on an LDEV list. In the LDEV display region are providedregions such as LDEV, Emulation, CVS, Size, and Cmd.Dev. A capacity anda command device of only LDEVs to which each LUN can be set aredisplayed.

The following will describe an actual processing procedure based on theitems displayed to the SVP 160 and the items input from the SVP 160 withreference to FIG. 26.

First the user selects a port for which path definition is desired (#1).With this, a list of LUNs that can be set to this port is displayed tothe SVP (#2). The user selects a LUN (system LU) for which pathdefinition is desired (#3). With this, a list of LDEVs that can be setto this LUN is displayed to the SVP (#4). In this case, only such LDEVsin an RAID as to meet capacity check conditions are displayed.

Furthermore, the user selects one of the LDEVs that can be set to theLUN (#5). With this, the SVP assigns the selected LDEV to this LUN (#6).This completes setting for one system LU. It is to be noted that ifthere are any other LUs, the above processing is repeated for each ofthese necessary LUs (#7).

Subsequently, the user selects an LUN (backup LU of the system LU) forwhich path definition is desired (#8). With this, a list of LDEVs thatcan be set to this LUN is displayed to the SVP. In this case, only suchLDEVs in the RAID as to meet the capacity check conditions aredisplayed.

Furthermore, the user selects one of the LDEVs that can be set to theLUN (#10). With this, the SVP assigns the selected LDEV to this LUN(#11). This completes setting for one backup LU of the system LU. It isto be noted that if there are any other LUs, the above processing isrepeated for each of these necessary LUs (#12).

Then, the SVP posts a suite of these set LUN and LDEV in a format of atable to all of NAS blades (#13). In this case, it posts also that theset LUN is a system LU. With this, in an NAS blade, the I/O processor(hereinafter written as IOP) allocates a backup LU of a system LU underthe control of another NAS blade of the set LUNs to an LUN that has ashade of meaning of “backup LU under the control of other NASblade/port” in its own table (#14). In this case, the LU must haveproperties required to be referenced by other NAS blade. At this stage,path definition is completed.

Subsequently, in the NAS blade, the IOP notifies the SVP of a tablerelated to the completed LUN-LDEV (#15). Furthermore, the user confirmspath definition (#16). Then, the SVP responds to the user with the tablerelated to the completed LUN-LDEV (#17).

<Processing for Definition of Paths of Various LUs Plus Backup LUs byMeans of NAS Blade (NASOS)-led Method>

The following will describe one example of processing for definition ofpaths of various LUs plus backup LUs by means of a NAS blade (NASOS)-ledmethod. FIG. 29 is a flowchart for showing processing for definition ofpaths of various LUs plus backup LUs by means of the NAS blade(NASOS)-led method.

Items to be displayed to the SVP are the same as those of FIG. 27 (basicscreen) and FIG. 28 (LUN-addition screen) in the above-mentionedAVP-and-NAS blade-led method and items to be input from the SVP are thesame as those of the above-mentioned SVP-and-NAS blade-led method. Thefollowing will describe an actual processing procedure with reference toFIG. 29.

According to this processing procedure, processing from (#21) to (#27)is the same as the above-mentioned processing from (#1) to (#7) andprocessing from (#37) to (#39) is the same as the above-mentionedprocessing from (#15) to (#17), so that their description is omittedhere and contents of processing from (#28) to (#36) are described below.

After (#27) is finished, the SVP posts a suite of set LUN and LDEV in aformat of a table to all of NAS blades (#28). In this case, it postsalso that the set LUN is a system LU. With this, in an NAS blade, theIOP extracts such LUn as to need backup of those set LUNs and searchesan RAID for LDEVs that have a necessary capacity (#29).

Subsequently, the SVP responds with numbers of LDEVs that meetconditions from a list table of the LDEVs in the RAID (#30). With this,in the NAS blade, it selects one of the LDEVs that meet the conditionsand updates an LUN-LDEV correlation table by using it as a backup LU(#31). Furthermore, it stored the updated LU-LDEV correlation table in ashared memory (#32). Then, it sets in the shared memory a flagindicating that the LUN-LDEV correlation table has been updated (#33).Then, the LUN-LDEV correlation table is posted to the SVP (#34).

Subsequently, in the other NAS blades, update of the LUN-LDEVcorrelation table is detected (#35). In this case, polling is used.Then, the IOP allocates an LU that it should reference of the updatedLUNs to an LUN that has a shade of meaning of “backup LU under thecontrol of other NAS blade/port” (#36). At this stage, path definitionis completed. Hereafter, processing of (#37) and the subsequent isperformed.

<Processing for Definition of Paths of Various LUs Plus Backup LUs byMeans of SVP-led Method>

The following will describe one example of processing for definition ofpaths for various LUs plus backup LUs by means of an SVP-led method withreference to FIG. 30. FIG. 30 is a flowchart for showing processing fordefinition of paths of various kinds of LUs plus backup LUs by means ofthe SVP-led method.

In this processing, items to be displayed to the SVP are the same asthose of FIG. 27 (basic screen) and FIG. 28 (LUN-addition screen) in theabove-mentioned AVP-and-NAS blade-led method and items to be input fromthe SVP are the same as those of the above-mentioned SVP-and-NASblade-led method. The following will describe an actual processingprocedure with reference to FIG. 30.

According to this processing procedure, processing from (#41) to (#51)is the same as the above-mentioned processing from (#1) to (#11) andprocessing from (#56) to (#57) is the same as the above-mentionedprocessing from (#16) to (#17), so that their description is omittedhere and contents of processing from (#52) to (#55) are described below.

After (#51) is finished, the SVP decides whether a set LUN needs to bereferenced by any other NAS blade (#52). If such is the case, itallocates an allocated LDEV to an LUN that has a shade of meaning of“backup LU under the control of other NAS blade/port” in the LUN-LDEVcorrelation table under the control of the other NAS blades (port)(#53). In this case, for each LUN or for each slot in which an NAS bladeis inserted, each LUN is defined as a fixed value. At this stage, pathdefinition is completed.

With this, setting for one backup LU of the system LU is completed. Itis to be noted that if there are other LUs, the above processing isrepeated for each of these necessary LUs (#54).

Subsequently, the SVP posts a suite of the set LUN and LDEV in a formatof a table to all of NAS blades (#55). In this case, it posts also thatthe set LUN is a system LU. Then, processing of (#56) and the subsequentis performed.

<Definition of User LU>

The following will describe one example of definition of a user LU withreference to FIGS. 31 and 32. FIG. 31 shows LUN definition for hostgroup #01 and FIG. 32 shows LUN definition for a user LU.

As shown in FIG. 31, in LUN definition for host group #01, an ordinaryvalue of 0 through 255 can be used but no LUN can be defined to an LDEVto which a system LU is already defined. Further, unless an LUN shown inFIG. 31 is defined to host group #00, no LUN can be defined to hostgroup #01. Specifically, LUNs #00 to FF each have contents for a userdata LU and a limitless LDEV minimum capacity.

As shown in FIG. 32, in definition of a user LU, as in the case of hostgroup #00, in each CHN 110, groups #01 of the two network I/Fs performcompletely the same LU definition. That is, the same LUN is defined tonetwork I/Fs that exits on the same CHN. It should be noted that to seta user LU, it is indispensable to set system LUs (LUNs #00, 01, 05, 06,and 08) of its CHN. (None of the system LUs (LUNs #00, 01, 05, 06, and08) exists, not user LU can be added). LUNs of host group #01 preparedfor user data can be set uninhibitedly as many as 256 starting from LUN#0 as in the case of an SAN environment.

<Module Configuration of Management Terminal and Function Outline>

The following will describe one example of a module configuration and afunction outline of the management terminal with reference to FIGS. 33and 34. FIG. 33 shows the module configuration of the managementterminal and FIG. 34 shows an outline of a function of each module.

As shown in FIG. 33, a configuration of modules which operate in themanagement terminal 160 comprises an LUN assignment function screenportion (hereinafter simply written as screen portion also) 751, an LUNassignment function execution portion (hereinafter simply written asexecution portion also) 752, a communication interface portion 753, etc.This management terminal 160 is connected to a package CPU via thecommunication interface portion 753 in the management terminal 160. Inthis management terminal 160, the screen portion 751 and the executionportion 752 provide such processing as given in FIG. 34.

For example, as for host groups, processing for defining group #00 as adefault (name: NAS-Sys) and processing for defining group #01 as adefault (name: User) are created at the execution portion. Further,processing of a host mode involves no-display and alteration suppressionat the screen portion and suppression at the execution portion.

Furthermore, as for LUNs, processing for adding a path in group #00 ispermitted at the screen portion to add paths for LUNs #00, 01, 05, 06,08, 09, 0A, 4B, 4C, and 4D. Further, processing for deleting a path ispermitted at the screen portion to behave based on an error command fromthe execution portion and inhibited at the execution portion in ancondition where there is a user LU. Furthermore, processing forconventional command device setting permits setting of LUN #05 at thescreen portion so that the other LDEVs may behave based on an error codefrom the execution portion and is inhibited at the execution portion.

Further, the path adding processing in group #01 is permitted at thescreen portion to behave based on an error code from the executionportion and inhibited at the execution portion in a condition where asystem LU is yet to be given. Further, processing for deleting a pathand the processing for conventional command device setting are permittedat the screen portion and the execution portion respectively.

<Details of LUN Definition>

The following will describe details of definition of an LUN. FIG. 35 isa diagram showing permission/inhibition of setting in an LUN definition.

(1) Permission/inhibition of Setting

LUN setting involves such restrictions as shown in FIG. 36 in setting ofconditions of a host group.

For example, if both group #00 (LUNS #00, 01, 05, 06, 08, 09, 0A, 4B;4C, and 4D) and group #01 are in a condition where there is no LUN,setting of LUN definition to group #00 can be added and deleted butcannot be done so to group #01. Further, in a condition where group #00has an LUN and group #01 has no LUN, setting of LUN definition to group#00 and group #01 can be added and deleted. Furthermore, in a conditionwhere both group #00 and group #01 have an LUN, setting of LUNdefinition to group #00 cannot be added or deleted but can be done so togroup #01. Further, in a condition where group #00 has no LUN and group#01 has an LUN, there is no setting of LUN definition to group #00 orgroup #01.

Further, automatically defined LUNs (#0B to 12, #1B to 22, #2B to 32,and #3B to 42) of a system LU can be added and deleted irrespective ofpath definition of group #01. Furthermore, to delete an LUN of group #00(system LU) of a relevant CHN owing to a decrease in number of packages,all of LUNs (including automatically set LUNs) of a relevant package areselected and deleted. It is to be noted that to delete a system LU, nouser LU of a relevant CHN must exist.

(2) Addition of System LU

Processing contents and checkpoints of each of LUNs# in addition of asystem LU are as follows.

For example, in processing of LUN #00, first addition of LUN #00 isrequested at the screen portion and the execution portion. In this case,a request is made to a first one of the two ports. Furthermore, an LDEVwith no path is caused to be selected at the screen portion and theexecution portion so that its capacity may be checked. Subsequently, atthe execution portion, related LUs (LUNs #0B to 12) to other CHNs areautomatically created and then LUNs (LUNs #0B to 12 and 1B to 22) areautomatically created from the other CHNs, to perform path definition tothe other port of the same CHN. Processing of LUN #01 is almost the sameas that of LUN #00 except that at the execution portion the related LUs(LUNs #1B to 22) to the other CHNs are automatically created and thenpath definition is performed to the other port of the same CHN.

Further, in processing of LUN #05, at the screen portion and theexecution portion, if a system LU is already set at other CHN, firstonly its LDEV is enabled to be selected and then, similarly, processingfrom addition requesting to capacity checking is performed.Subsequently, at the screen portion, if no command device is set, acommand device is set, and then at the execution portion, pathdefinition is performed to the other port of the same CHN. Processing ofLUNs #06, 08, 4B, 4C, and 4D is the same except that command devicesetting is unnecessary at LUN #05.

Further, processing of LUNs #09 and 0A is the same except that relatedLUs that are automatically created from the other CHNs after related LUsto other CHNs are automatically created at LUN #00 are different. Inprocessing of LUN #09, related LUNs #2B to 32 to other CHNs areautomatically created and then related LUNs #0B to 12, #1B to 22, #2B to32, and 3B-42 are automatically created from the other CHNs. Inprocessing of LUN #0A, related LUNs #3B to 42 to other CHNs areautomatically created and then related LUNs #0B to 12, #1B to 22, #2B to32, and #3B to 42 are automatically created from the other CHNs.

In this addition of a system LU, a command device is set only to LUN#05. In command device setting to LUN #05, if a command device isalready set, it is left as it is. If a command device not set isselected, the screen portion makes a request to the execution portion toset a command device. It is to be noted that command device setting andreleasing for LUN #05 can be performed in the same way as for aconventional LDEV.

(3) Deletion of System LU

In deletion of a system LU, processing contents and checkpoints of eachof LUNs# are as follows.

For example, in processing of LUN #00, first deletion of LUN #00 isrequested at the screen portion and the execution portion. In this case,a request is made to a first one of the two ports. Subsequently, at theexecution portion, a path to the other port of the same CHN is deletedand LUs (LUNs #0B to 12) related to other CHNs are also deleted.Processing of LUN #01 is the same except that as LUs related to theother CHNs in LUN #00, LUNs #1B to 22 are deleted.

Further, processing of LUNs #05, 06, 08, 4B, 4C, and 4D is the sameexcept deleting also the LUs related to the other CHNs in LUN #01becomes unnecessary.

Further, processing of LUNs #09 and 0A is the same except that differentLUs related to the other CHNs in LUN #01 are also deleted. In processingof LUN #09, related LUNs #2B to 32 of the other CHNs are deleted. Inprocessing of LUN #0A, related LUNs #3B to 42 of the other CHNs aredeleted.

Further, in processing of the other LUNs, deletion of an automaticallycreated path of a relevant package is permitted.

In this deletion of a system LU, deletion of an LUN of a relevantpackage is permitted only when all of the system LUs are selected. Toenable deleting a system LU, no user LU must exist in a relevantpackage.

(4) Addition of User LU

In addition to a user LU, processing contents and checkpoints are asfollows.

First, a path is defined at the screen portion and the executionportion. In this case, a request is made to a first one of the twoports. Then, at the execution portion, a path to the other port of thesame CHN is also deleted. It is to be noted that definition to anintermediate volume is impossible at the screen portion and theexecution portion and path definition without a system LU is impossibleeither at the execution portion.

(5) Deletion of User LU

In deletion of a user LU, processing contents and checkpoints are asfollows.

First, a path is deleted at the screen portion and the executionportion. In this case, a request is made to a first one of the twoports. Then, at the execution portion, a path to the other port of thesame CHN is also deleted.

<Effects of the Present Embodiment>

(1) It is possible to provide a storage unit system that can beconnected to different kinds of networks such as information processingapparatuses (1) 200 through (3) 200 connected via the LAN 400,information processing apparatuses (3) 200 through (4) 200 connected viathe SAN 500, and an information processing apparatus (5) 200 connectednot via a network such as the LAN 400 or the SAN 500 and a method tocontrol replication of a system region of a storage device control unitrequired in such a storage unit system.

(2) It is possible to explicitly separate a system LU and a user LU fromeach other by setting by a maintenance man or a user from the managementterminal 160 etc. That is, to conceal a system LU from a client, themanagement terminal 160 etc. provides this LU with an interface fordefining a path by explicitly specifying a system LU and a user LU. Inaccordance with distinction between system LUs and user LUs that is settherethrough, a micro-program can manage access for management from anNASOS and data access from the user in a condition where they areseparated from each other.

(3) It is possible to automatically define a path and set a decrease inthe number of the paths so that a backup LU can be specified only for asystem LU and it can be accessed from each package in accordance with aconstant policy. That is, to avoid occurrence of an event where anfail-over operation is impossible at all clusters owing to a fault of asystem LU, a backup of the system LU is created in the same frame. Inthis case, to effectively utilize backed up data, such a function isprovided as to semi-automatically perform LU path definition from eachpackage in accordance with the constant policy.

Further, a mistake of decreasing the number of paths irrespective ofexistence of a system can be prevented both for a system LU and a userLU.

As described above, the invention made by the inventors has beenconcretely described based on the embodiment. However, needless to say,the present invention is not limited to the above-mentioned embodimentand can be variously modified and altered without departing from thegist thereof.

1. A disk array device comprising: a plurality of storage devices forstoring data: a storage device control unit for controlling a data writeor read operation to said plurality of storage devices; a connectionportion connected to said storage device control unit; a plurality ofchannel control portions for receiving a write or read request from anexternal host device, converting file-level data sent from said hostdevice into block-level data, and transferring it to said plurality ofstorage devices; a cache memory temporarily saving data exchangedbetween said plurality of channel control portions and said storagedevice control unit; and a management terminal for setting a logicalconfiguration of said plurality of storage devices, wherein said channelcontrol portions and/or said storage device control unit form a systemLU which is a storage region for storing control information in the diskarray device itself, a user LU which is a storage region for writingwrite data sent from said host device and a backup LU which is a storageregion for backing up said control information stored in said system LU,and based on at least one instruction sent from said managementterminal, wherein said channel control portions, said storage devicecontrol unit and/or said management terminal provide a function toautomatically define a path of said backup LU with respect to saidsystem LU and to backup the control information stored in said system LUto said backup LU.
 2. The disk array device according to claim 1,wherein said function to automatically define the path of said system LUis realized by said management terminal and said plurality of channelcontrol portions, said management terminal has a function to assign saidsystem LU of which a path definition is desired, to a settable LDEV of aplurality of LDEVs, and said plurality of channel control portions eachhave a function to automatically define a path of said system LU withrespect to said backup LU of said settable LDEV assigned by saidmanagement terminal.
 3. The disk array device according to claim 1,wherein said function to automatically define the path of said system LUis realized by said plurality of channel control portions, and saidplurality of channel control portions each have a function to assignsaid system LU for which a path definition is desired, to a settableLDEV of a plurality of LDEVs, and to automatically define a path of saidsystem LU with respect to said backup LU of said settable LDEV assigned.4. The disk array device according to claim 1, wherein said function toautomatically define the path of said system LU is realized by saidmanagement terminal, and said management terminal has a function toassign said system LU for which a path definition is desired, to asettable LDEV of a plurality of LDEVs, and to automatically define apath of said system LU with respect to said backup LU of said settableLDEV assigned.
 5. The disk array device according to claim 1, whereinthe control information stored in said system LU is OS information, andsaid OS information is backed up to said backup LU.
 6. The disk arraydevice according to claim 1, wherein the control information stored insaid system LU is dump information, and said dump information is backedup to said backup LU.
 7. The disk array device according to claim 1,wherein the control information stored in said system LU is commanddevice information, and said command device information is backed up tosaid backup LU.
 8. The disk array device according to claim 1, whereinthe control information stored in said system LU is fault information,and said fault information is backed up to said backup LU.
 9. The diskarray device according to claim 1, wherein the control informationstored in said system LU is cluster-shared information, and saidcluster-shared information is backed up to said backup LU.
 10. Acontrolling method of a disk array device, said disk array devicecomprising: a plurality of storage devices for storing data: a storagedevice control unit for controlling a data write or read operation tosaid plurality of storage devices; a connection portion connected tosaid storage device control unit; a plurality of channel controlportions for receiving a write or read request from an external hostdevice, converting file-level data sent from said host device intoblock-level data, and transferring it to said plurality of storagedevices; a cache memory temporarily saving data exchanged between saidplurality of channel control portions and said storage device controlunit; and a management terminal for setting a logical configuration ofsaid plurality of storage devices, wherein, said channel controlportions and/or said storage device control unit form a system LU whichis a storage region for storing control information in the disk arraydevice itself, a user LU which is a storage region for writing writedata sent from said host device are settable, and a backup LU which is astorage region for backing up said control information stored in saidsystem LU, and based on at least one instruction sent from saidmanagement terminal, wherein said channel control portions, said storagedevice control unit and/or said management terminal provide a functionis provided to automatically define a path of said backup LU withrespect to said system LU and to backup the control information storedin said system LU to said backup LU.
 11. The controlling method of adisk array device according to claim 10, wherein said function toautomatically define the path of said system LU is realized by saidmanagement terminal and said plurality of channel control portions, saidmanagement terminal assigns said system LU of which a path definition isdesired, to a settable LDEV of a plurality of LDEVs, and said pluralityof channel control portions each define automatically a path of saidsystem LU with respect to said backup LU of said settable LDEV assignedby said management terminal.
 12. The controlling method of a disk arraydevice according to claim 10, wherein said function to automaticallydefine the path of said system LU is realized by said plurality ofchannel control portions, and said plurality of channel control portionseach assign said system LU for which a path definition is desired, to asettable LDEV of a plurality of LDEVs, and define automatically a pathof said system LU with respect to said backup LU of said settable LDEVassigned.
 13. The controlling method of a disk array device according toclaim 10, wherein said function to automatically define the path of saidsystem LU is realized by said management terminal, and said managementterminal assigns said system LU for which a path definition is desired,to a settable LDEV of a plurality of LDEVs, and defines automatically apath of said system LU with respect to said backup LU of said settableLDEV assigned.
 14. The controlling method of a disk array deviceaccording to claim 10, wherein the control information stored in saidsystem LU is OS information, and said OS information is backed up tosaid backup LU.
 15. The controlling method of a disk array deviceaccording to claim 10, wherein the control information stored in saidsystem LU is dump information, and said dump information is backed up tosaid backup LU.
 16. The controlling method of a disk array deviceaccording to claim 10, wherein the control information stored in saidsystem LU is command device information, and said command deviceinformation is backed up to said backup LU.
 17. The controlling methodof a disk array device according to claim 10, wherein the controlinformation stored in said system LU is fault information, and saidfault information is backed up to said backup LU.
 18. The controllingmethod of a disk array device according to claim 10, wherein the controlinformation stored in said system LU is cluster-shared information, andsaid cluster-shared information is backed up to said backup LU.
 19. Thedisk array device according to claim 1, wherein said management terminalhas a function to specify said system LU and said user LU in order toset a path definition with respect to a plurality of LDEVs.
 20. The diskarray device according to claim 10, wherein said management terminal hasa function to specify said system LU and said user LU in order to set apath definition with respect to a plurality of LDEVs.